# PHP Operators

PHP Operator is a symbol i.e used to perform operations on operands. In simple words, operators are used to perform operations on variables or values. For example:

- $num=10+20;//+ is the operator and 10,20 are operands

In the above example, + is the binary + operator, 10 and 20 are operands and $num is variable.

PHP Operators can be categorized in following forms:

- Arithmetic Operators
- Assignment Operators
- Bitwise Operators
- Comparison Operators
- Incrementing/Decrementing Operators
- Logical Operators
- String Operators
- Array Operators
- Type Operators
- Execution Operators
- Error Control Operators

We can also categorize operators on behalf of operands. They can be categorized in 3 forms:

**Unary Operators:**works on single operands such as ++, — etc.**Binary Operators:**works on two operands such as binary +, -, *, / etc.**Ternary Operators:**works on three operands such as “?:”.

## Arithmetic Operators

The PHP arithmetic operators are used to perform common arithmetic operations such as addition, subtraction, etc. with numeric values.

Operator | Name | Example | Explanation |
---|---|---|---|

+ | Addition | $a + $b | Sum of operands |

– | Subtraction | $a – $b | Difference of operands |

* | Multiplication | $a * $b | Product of operands |

/ | Division | $a / $b | Quotient of operands |

% | Modulus | $a % $b | Remainder of operands |

** | Exponentiation | $a ** $b | $a raised to the power $b |

The exponentiation (**) operator has been introduced in PHP 5.6.

## Assignment Operators

The assignment operators are used to assign value to different variables. The basic assignment operator is “=”.

Operator | Name | Example | Explanation |
---|---|---|---|

= | Assign | $a = $b | The value of right operand is assigned to the left operand. |

+= | Add then Assign | $a += $b | Addition same as $a = $a + $b |

-= | Subtract then Assign | $a -= $b | Subtraction same as $a = $a – $b |

*= | Multiply then Assign | $a *= $b | Multiplication same as $a = $a * $b |

/= | Divide then Assign (quotient) |
$a /= $b | Find quotient same as $a = $a / $b |

%= | Divide then Assign (remainder) |
$a %= $b | Find remainder same as $a = $a % $b |

## Bitwise Operators

The bitwise operators are used to perform bit-level operations on operands. These operators allow the evaluation and manipulation of specific bits within the integer.

Operator | Name | Example | Explanation |
---|---|---|---|

& | And | $a & $b | Bits that are 1 in both $a and $b are set to 1, otherwise 0. |

| | Or (Inclusive or) | $a | $b | Bits that are 1 in either $a or $b are set to 1 |

^ | Xor (Exclusive or) | $a ^ $b | Bits that are 1 in either $a or $b are set to 0. |

~ | Not | ~$a | Bits that are 1 set to 0 and bits that are 0 are set to 1 |

<< | Shift left | $a << $b | Left shift the bits of operand $a $b steps |

>> | Shift right | $a >> $b | Right shift the bits of $a operand by $b number of places |

## Comparison Operators

Comparison operators allow comparing two values, such as number or string. Below the list of comparison operators are given:

Operator | Name | Example | Explanation |
---|---|---|---|

== | Equal | $a == $b | Return TRUE if $a is equal to $b |

=== | Identical | $a === $b | Return TRUE if $a is equal to $b, and they are of same data type |

!== | Not identical | $a !== $b | Return TRUE if $a is not equal to $b, and they are not of same data type |

!= | Not equal | $a != $b | Return TRUE if $a is not equal to $b |

<> | Not equal | $a <> $b | Return TRUE if $a is not equal to $b |

< | Less than | $a < $b | Return TRUE if $a is less than $b |

> | Greater than | $a > $b | Return TRUE if $a is greater than $b |

<= | Less than or equal to | $a <= $b | Return TRUE if $a is less than or equal $b |

>= | Greater than or equal to | $a >= $b | Return TRUE if $a is greater than or equal $b |

<=> | Spaceship | $a <=>$b | Return -1 if $a is less than $b Return 0 if $a is equal $b Return 1 if $a is greater than $b |

## Incrementing/Decrementing Operators

The increment and decrement operators are used to increase and decrease the value of a variable.

Operator | Name | Example | Explanation |
---|---|---|---|

++ | Increment | ++$a | Increment the value of $a by one, then return $a |

$a++ | Return $a, then increment the value of $a by one | ||

— | decrement | –$a | Decrement the value of $a by one, then return $a |

$a– | Return $a, then decrement the value of $a by one |

## Logical Operators

The logical operators are used to perform bit-level operations on operands. These operators allow the evaluation and manipulation of specific bits within the integer.

Operator | Name | Example | Explanation |
---|---|---|---|

and | And | $a and $b | Return TRUE if both $a and $b are true |

Or | Or | $a or $b | Return TRUE if either $a or $b is true |

xor | Xor | $a xor $b | Return TRUE if either $ or $b is true but not both |

! | Not | ! $a | Return TRUE if $a is not true |

&& | And | $a && $b | Return TRUE if either $a and $b are true |

|| | Or | $a || $b | Return TRUE if either $a or $b is true |

## String Operators

The string operators are used to perform the operation on strings. There are two string operators in PHP, which are given below:

Operator | Name | Example | Explanation |
---|---|---|---|

. | Concatenation | $a . $b | Concatenate both $a and $b |

.= | Concatenation and Assignment | $a .= $b | First concatenate $a and $b, then assign the concatenated string to $a, e.g. $a = $a . $b |

## Array Operators

The array operators are used in case of array. Basically, these operators are used to compare the values of arrays.

Operator | Name | Example | Explanation |
---|---|---|---|

+ | Union | $a + $y | Union of $a and $b |

== | Equality | $a == $b | Return TRUE if $a and $b have same key/value pair |

!= | Inequality | $a != $b | Return TRUE if $a is not equal to $b |

=== | Identity | $a === $b | Return TRUE if $a and $b have same key/value pair of same type in same order |

!== | Non-Identity | $a !== $b | Return TRUE if $a is not identical to $b |

<> | Inequality | $a <> $b | Return TRUE if $a is not equal to $b |

## Execution Operators

PHP has an execution operator **backticks (“)**. PHP executes the content of backticks as a shell command. Execution operator and **shell_exec()** give the same result.

Operator | Name | Example | Explanation |
---|---|---|---|

“ | backticks | echo `dir`; | Execute the shell command and return the result. Here, it will show the directories available in current folder. |

#### Note: Note that backticks (“) are not single-quotes.

## Error Control Operators

PHP has one error control operator, i.e., **at (@) symbol**. Whenever it is used with an expression, any error message will be ignored that might be generated by that expression.

Operator | Name | Example | Explanation |
---|---|---|---|

@ | at | @file (‘non_existent_file’) | Intentional file error |

## PHP Operators Precedence

Let’s see the precedence of PHP operators with associativity.

Operators | Additional Information | Associativity |
---|---|---|

clone new | clone and new | non-associative |

[ | array() | left |

** | arithmetic | right |

++ — ~ (int) (float) (string) (array) (object) (bool) @ | increment/decrement and types | right |

instanceof | types | non-associative |

! | logical (negation) | right |

* / % | arithmetic | left |

+ – . | arithmetic and string concatenation | left |

<< >> | bitwise (shift) | left |

< <= > >= | comparison | non-associative |

== != === !== <> | comparison | non-associative |

& | bitwise AND | left |

^ | bitwise XOR | left |

| | bitwise OR | left |

&& | logical AND | left |

|| | logical OR | left |

?: | ternary | left |

= += -= *= **= /= .= %= &= |= ^= <<= >>= => | assignment | right |

and | logical | left |

xor | logical | left |

or | logical | left |

, | many uses (comma) | left |